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authorFabrice Bellard <fabrice@bellard.org>2002-11-25 19:07:40 +0000
committerFabrice Bellard <fabrice@bellard.org>2002-11-25 19:07:40 +0000
commitabac6175916c57f59ddb51ffe41bfd1d9851fe38 (patch)
tree8fc5b70a143f0f74468c353afbf043d7e104cdc0 /libavformat/crc.c
parent57fc25764261abe71b6cf7571eca182f8acf5795 (diff)
downloadffmpeg-abac6175916c57f59ddb51ffe41bfd1d9851fe38.tar.gz
renamed libav to libavformat
Originally committed as revision 1276 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavformat/crc.c')
-rw-r--r--libavformat/crc.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/libavformat/crc.c b/libavformat/crc.c
new file mode 100644
index 0000000000..553ab537cb
--- /dev/null
+++ b/libavformat/crc.c
@@ -0,0 +1,111 @@
+/*
+ * CRC decoder (for codec/format testing)
+ * Copyright (c) 2002 Fabrice Bellard.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include "avformat.h"
+
+/* adler32.c -- compute the Adler-32 checksum of a data stream
+ * Copyright (C) 1995 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#define BASE 65521L /* largest prime smaller than 65536 */
+#define NMAX 5552
+/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
+
+#define DO1(buf) {s1 += *buf++; s2 += s1;}
+#define DO2(buf) DO1(buf); DO1(buf);
+#define DO4(buf) DO2(buf); DO2(buf);
+#define DO8(buf) DO4(buf); DO4(buf);
+#define DO16(buf) DO8(buf); DO8(buf);
+
+static UINT32 adler32(UINT32 adler, UINT8 *buf, unsigned int len)
+{
+ unsigned long s1 = adler & 0xffff;
+ unsigned long s2 = (adler >> 16) & 0xffff;
+ int k;
+
+ if (buf == NULL) return 1L;
+
+ while (len > 0) {
+ k = len < NMAX ? len : NMAX;
+ len -= k;
+ while (k >= 16) {
+ DO16(buf);
+ k -= 16;
+ }
+ if (k != 0) do {
+ DO1(buf);
+ } while (--k);
+ s1 %= BASE;
+ s2 %= BASE;
+ }
+ return (s2 << 16) | s1;
+}
+
+typedef struct CRCState {
+ UINT32 crcval;
+} CRCState;
+
+static int crc_write_header(struct AVFormatContext *s)
+{
+ CRCState *crc = s->priv_data;
+
+ /* init CRC */
+ crc->crcval = adler32(0, NULL, 0);
+
+ return 0;
+}
+
+static int crc_write_packet(struct AVFormatContext *s,
+ int stream_index,
+ unsigned char *buf, int size, int force_pts)
+{
+ CRCState *crc = s->priv_data;
+ crc->crcval = adler32(crc->crcval, buf, size);
+ return 0;
+}
+
+static int crc_write_trailer(struct AVFormatContext *s)
+{
+ CRCState *crc = s->priv_data;
+ char buf[64];
+
+ snprintf(buf, sizeof(buf), "CRC=%08x\n", crc->crcval);
+ put_buffer(&s->pb, buf, strlen(buf));
+ put_flush_packet(&s->pb);
+ return 0;
+}
+
+static AVOutputFormat crc_format = {
+ "crc",
+ "crc testing format",
+ NULL,
+ "",
+ sizeof(CRCState),
+ CODEC_ID_PCM_S16LE,
+ CODEC_ID_RAWVIDEO,
+ crc_write_header,
+ crc_write_packet,
+ crc_write_trailer,
+};
+
+int crc_init(void)
+{
+ av_register_output_format(&crc_format);
+ return 0;
+}